The 2017 LaCrosse (second year of third-gen platform) shares GM's 8-speed auto and generally solid bones, but the 3.6L V6 has documented piston/ring issues leading to oil consumption and catastrophic failure, while both powertrains can suffer transmission fluid cooler leaks that quietly damage the 8-speed.
3.6L V6 Piston Ring / Oil Consumption Failure
Occasional · high severityTypical onset: 70,000-130,000 mi
Symptoms: Excessive oil consumption (1 qt per 1,000 mi or worse), Blue smoke on cold start or under load, Check engine light for misfires (P0300-series codes), Eventual catastrophic failure with metal in oil
Fix: GM's 3.6L high-feature V6 suffers piston ring land cracking and carbon buildup. Temporary fix is piston ring cleaning service (6-8 hrs), but most end up needing short block or full engine replacement (18-24 hrs). Some dealerships have done goodwill assistance outside warranty on documented cases.
Estimated cost: $6,500-9,500
Transmission Oil Cooler Internal Leak
Common · high severityTypical onset: 60,000-110,000 mi
Symptoms: Milky or strawberry-colored transmission fluid, Transmission slipping or delayed engagement, Coolant level dropping without external leaks, Trans fault messages or limp mode
Fix: The 8L45/8L90 trans cooler develops internal cracks allowing coolant and ATF to mix. Requires cooler replacement, full trans fluid flush (sometimes converter replacement if contaminated), and radiator inspection. Caught early: 4-6 hrs. If trans is damaged: add 12-16 hrs for rebuild or replacement.
Estimated cost: $1,200-2,800 (early catch), $4,500-7,000 (with trans damage)
Transmission Mount Failure (Rear)
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Loud clunk when shifting from Park to Drive or Reverse, Vibration at idle in gear, Excessive driveline movement on acceleration/deceleration
Fix: The rear transmission mount (hydraulic type) collapses or tears, especially on V6 models with more torque. Replacement is straightforward but requires supporting the transmission. 2-3 hrs labor.
Estimated cost: $350-600
Electric Power Steering Assist Failure
Occasional · high severitySymptoms: Sudden loss of power steering assist (steering becomes very heavy), Service StabiliTrak and power steering warning messages, May occur intermittently or permanently
Fix: NHTSA recall 19V-707 covered some units for steering gear internal short. Outside recall scope, failures require electric steering gear replacement (rack assembly with motor integrated). 3-4 hrs labor, but part is expensive.
Estimated cost: $1,800-2,900
Rear Suspension Control Arm Bushing Deterioration
Occasional · medium severityTypical onset: 70,000-120,000 mi
Symptoms: Clunking or popping from rear on bumps, Wandering or unstable feel at highway speeds, Uneven rear tire wear (inner edge), Alignment won't hold or is out-of-spec
Fix: Rear lower control arm bushings (multi-link suspension) crack and separate, especially in salt-belt states. Some bushings are pressed-in replaceable (2 hrs per side), others require full control arm replacement (1.5 hrs per side). Alignment required after.
Estimated cost: $600-1,200 (both sides plus alignment)
Fuel Pump / Fuel Filter Assembly Failure
Rare · medium severityTypical onset: 80,000-140,000 mi
Symptoms: Hard starting, especially when hot, Engine stumbling or cutting out under acceleration, Fuel pump whine audible from rear seat area, Check engine light with low fuel pressure codes (P0087)
Fix: In-tank fuel pump module (pump, filter, and sender integrated) fails. Requires dropping the fuel tank on AWD models or accessing through trunk cutout on FWD. 3-4 hrs labor. Use AC Delco or OE-equivalent to avoid repeat failures.
Estimated cost: $800-1,400
The 2.5L I4 FWD version is a safe bet if you can live with modest power; avoid the 3.6L V6 unless you have documentation of recent engine work or are prepared for a $7k-$9k engine replacement gamble.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.